Composite metallic plates of titanium and dissimilar mother metals



"Nov. 1, 1966 MASAYOSHI KAWAI ETAL 3,282,661

COMPOSITE METALLIC PLATES OF TITANIUM AND DISSIMILAR MOTHER METALS FiledAug. 10, 1964 2 Sheets-Sheet 1 Nov. 1, 1966 MASAYOSHI KAWAI ETAL3,282,661

COMPOSITE METALLIC PLATES 0F TITANIUM AND DIS-SIMILAR MOTHER METALSFiled Aug. 10, 1964 2 Sheets-Sheet 2 United States Patent 3,232,661COMPQSITE METALLHC PLATES 0F TITANIUM AND DlSSIMlLAR MOTHER METALSMasayoshi Kawai, Kiyohiito Kizuki, Hideo Hara, Hachiro Kobayalcawa, andKameichi Shimizu, Nagasaki, Japan,

assignors to Mitsubishi Seiko Kabushiki-Kaisha, Tokyo,

Japan, a Japanese company Filed Aug. 10, 1964, er. No. 389,822 Claimspriority, application Japan, Mar. 29, 1962, 37/12,387, 37/12,388 5Claims. (Cl. 29196) This application is a continuation-impart of ourapplications Serial No. 266,998, filed March 21, 1963, now abandoned,and Serial No. 266,999, filed March 21, 1963, now abandoned.

This invention relates to a composite metallic plate made up of titaniumand a dissimilar mother metal and more particularly to such a platewhich has a titanium veneer bonded to a plate of dissimilar mother metaleither directly or through an intermediate layer of bonding metal.

Titanium has many uses because it has excellent anticorrosive propertieswith respect to various media, high resistance to corrosion in the voidsthereof, at boundaries, at stress points and at contact points and thelike, and it is light in weight, has high strength and can be given abrilliant lustre. Thus, as a corrosion resisting metal, titanium has animportant position in manufacturing chemical apparatus and othermachines used in the fields of industry utilizing sea water, thepetrochemical industry and the like. In addition, it is increasinglyutilized for ornamental purposes and in manufacturing parts of medicalapparatus and aircraft.

From an economic standpoint, in order to save expensive titanium and forpurposes or rigidity, stiffness, weldability, strength and the likerequired in structures where titanium is used, it is frequentlydesirable to provide .a composite metallic plate having a titaniumveneer bonded to a plate of dissimilar mother metal on either face or onboth faces.

Heretofore, numerous processes for bonding a titanium veneer orllaminating a veneer to a sheet or plate of dissimilar mother metal havebeen proposed and are presently being used.

As is well known, titanium is different from many other metals in thatit is very high in its chemical reactivity. Accordingly, it isrecognized that joints between titanium and other metals become brittle,with the result that it is very difficult to ensure good adherence ofthe metals at such joints. This is principallybased upon the fact thattitanium has very high affinities for oxygen, hydrogen, nitrogen, etc.and that, when titanium contacts any dissimilar metal to form therewithan alloy which comprises very frequently an intermetallic compound,there are many cases either where the titanium lamination exfoliatesfrom the plate of dissimilar mother metal during veneering or where theresulting product has poor workability.

Accordingly, it is the chief object of the invention to provide animproved composite plate of titanium and a dissimilar mother metalhaving good adherence between the metals and excellent workability.

With this object in view, the invention resides in a composite metallicplate having a titanium veneer bonded either directly to a plate ofdissimilar mother metal on at least one face, or through said plate ofdissimilar mother metal to a base plate of dissimilar metal. When themother metal is used as a bonding material it is an alloy consistingessentially of iron and a metal taken from the group consisting of .3 to19.0% by weight of molybdenum, from .3 to 20.0% by weight of vanadium,from .3 to 15% 3,282,661 Patented Nov. 1, i966 by weight of niobium,from .3 to 8.0% by weight of zirconium and from .3 to 18.0% by weight oftungsten. When the mother metal is not bonded to a base plate, themother metal is an alloy consisting essentially of iron and a metaltaken from the group consisting of from .3 to 10.0% by weight ofmolybdenum, from .3 to 10.0% by weight of vanadium, from .3 to 10.0% byweight of niobium, from .3 to 6.0 by weight of zirconium, and from .3 to10.0 by weight of tungsten respectively.

The invention will be more readily apparent from the following detaileddescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a schematic side elevation view, partly in cross section, ofan assembly of a titanium veneer, a base plate of dissimilar :metal andan intermediate layer of dissimilar mother metal acting as a bondingmaterial disposed therebetween, the assembly being processed inaccordance with the teachings of the invention;

FIG. 2 is a view similar to FIG. 1 but illustrating a modification ofthe invention in which two plates are produced at the same time;

FIG. 3 is a schematic side elevation view, partly in cross section, ofan assembly of a titanium veneer and a plate of dissimilar mother metal,the .assembly being processed in accordance with the teachings of theinvention; and

FIG. 4 is a view similar to FIG. 3 but illustrating a modification ofthe invention in which two plates are produced at the same time.

The invention is based upon the discovery that particular iron alloyswill adhere excellently to titanium.

According to the teachings of the invention a composite metallic platehaving a titanium veneer or lamination is bonded either directly to .aplate of dissimilar mother metal or through said plate to a base plateof dissimilar metal as will be in detail described hereinafter.

As a result of an enormous number of experiments conducted over a longperiod of time, it has been found that a variety of iron alloys can beused as metallic bonding materials, the iron being alloyed with a metaltaken from the group consisting of molybdenum, vanadium, niobium,zirconium and tungsten, to form composite metallic plates with titanium.As base metals for such composite metallic plates there can be used ironand steel materials such as ordinary steels and low alloy steels, forexample ASTM type A201GB steel.

Where a mother metal is used as a bonding material between a titaniumplate and a base plate, the metal of the abovementioned elements whichis used should be contained in the bonding iron alloy in an amount of atleast 3% based upon the total weight of the alloy. In the case wheremolybdenum, vanadium, niobium, zirconium or tungsten is used, in anamount less than 3% by weight in the iron alloys used as intermediatebonding metals, the results of the experiments indicated that theresulting products were poor insofar as adherence of the mother alloyswhich were used to the titanium was concerned.

On the other hand, the upper limits for the amounts of the aforesaidrespective metals contained in the iron alloys have been determined bythe deformability of the bonding iron alloys when the resulting productshave been subjected to various mechanical workings. In other words, theupper limit for the content of a particular metal as above described hasbeen determined by a compromise between the amount thereof and therespective amounts of carbon, manganese, silicon, phosphorus, sulfuretc. originally contained in the iron alloys used as bonding materialsso as to impart to the iron alloys a workability .as compared with thebase metal such that the finished composite metZlllilC plates will notbe brittle.

Thus the upper limits for the amounts of the elements referred to in theiron alloys used as bonding materials have been determined to be 19%,20.0%, 15.0%, 8.0% and 18.0% for molybdenum, vanadium, niobium,zirconium and tugnsten respectively, these percentages being based uponthe total weight of the alloy.

In order to obtain a correlation between the amount of each of theabovementioned elements contained in the bonding iron alloys and theadherence properties of the alloys with respect to titanium, additionalexperiments were conducted. As a result, it has been found that as theamount of each element contained in the iron alloy is increased up to acertain limit, the adherence of the alloy to titanium is increased to acertain extent, with a further increase in the amount of the elementbeyond the limit not appreciably varying the adherence of the alloy.Also from both the phase diagrams for the iron alloys and theexperiments it has been verified that any excess of the alloyingelements adversely affects the hot workability of the bonding materialswhen bonding sheets are prepared. Therefore, considering all threeaspects, adherence, economy and workability, the amounts of molybdenum,vanadium, niobium, zirconium and tungsten should preferably range from1.0 to 5.0%, from 1.0 to 5.0%, from .5 to 2.0%, from .5 to 2.5% and from1.0 to 2.0% respectively, on the basis of the total weight of the alloy.

It has also been found that a variety of iron alloys can be used asmother metals without further bonding to a base plate, the iron beingalloyed with a metal also taken from said group consisting ofmolybdenum, vanadium, niobium, zirconium and tungsten to form compositemetallic plates with titanium. The amount of any one of such elementscontained in the iron alloy should range from .3 to 10.0% for each ofmolybdenum, vanadium, niobium and tungsten, and from .3 to 6.0% forzirconium, based upon the total weight of the alloy.

When the mother metal was used without further bonding to a base plate,where any one of molybdenum, vanadium, niobium, zirconium and tungstenwas present in an amount less than .3% by weight of the iron alloy usedas the mother metal, the results of the experiments indicated that theresulting products were poor in adherence of the mother metal to thetitanium. On the other hand, the upper limits for amounts of theaforesaid respective elements contained in the iron alloys have beendetermined by the deformability of the mother metals or iron alloys whenthe resulting products were subjected to various mechanical workings. Inother words, the up per limit for the content of a particular element asabove described has been determined by a compromise between the amountthereof and the respective amounts of carbon, manganese, silicon,phosphorus, sulfur etc. originally contained in the iron alloys to beused as mother metals so as to impart to the iron alloys a workabilitysuch that the finished composite metallic plates will not be brittle.

In order to obtain a correlation between the amount of each of theabovementioned elements contained in iron alloys and the adherenceproperties of the mother metal alloys to titanium, additionalexperiments were conducted. As a result, it has been found that, as theamount of each element contained in the mother metal iron alloy isincreased up to a certain limit, the adherence of the alloy to titaniumis increased to a certain extent, with a further increase in the amountof the element beyond the limit not appreciably changing the adherenceof the alloy of the mother metal. Any excess of the respective alloyingelements tends to make the mother metal iron alloy brittle. Therefore,taking into account the adherence, economy and workability, the amountsof molybdenum, vanadium, niobium, zirconium and tungsten shouldpreferably range from 1.0 to 4.0%, from 1.0 to 3.0%, from .5 to 1.5%,from .5 to 1.0% and from 1.0 to 1.5% respectively, on the basis of thetotal weight of the mother metal alloy.

In practicing the invention when the mother metal is to be bonded to abase plate, a titanium sheet, an intermediate layer of any one of thebonding iron alloys described hereinbefore, and a base plate of suitablemetal are superposed upon each other to form a stacked assembly. Thenthe stacked assembly is heated and hot rolled to produce a compositemetallic plate.

In practicing the invention, when the mother metal plate is not to bebonded to a base plate, a titanium sheet is superposed upon a mothermetal plate composed of anyone of the iron alloys as hereinbeforedescribed to form a stacked assembly. Then the stacked assembly isheated and rolled to produce a composite metallic plate.

Referring now to FIG. 1 of the drawings, there is illustrated anassembly of a titanium veneer superposed upon a mother metal plate whichacts as an intermediate layer of a metallic bonding material accordingto the invention, and upon a base plate of a dissimilar metal. Atitanium sheet, an intermediate mother metal sheet of metallic bondingmaterial, a metal base plate and a cover plate of any suitable materialare machined to the desired dimensions respectively. Then those faces ofthe titanium sheet, the intermediate mother metal sheet of bondingmaterial and the base plate to be attached to each other aremechanically polished and chemically cleaned.

As shown in FIG. 1, the titanium sheet 1 thus treated is put upon themother metal bonding sheet 2 also preliminarily treated and superposedupon the metal base plate 3 also treated, with the faces of the memberswhich are in contact with each other being in register. Then the coverplate 4 is superposed on the exposed face of the titanium sheet 1 with aparting sheet of any suitable material 5 sandwiched therebetween andwith a plurality of spacers of any suitable material 6 interposedbetween the cover plate 4 and the metal base plate 3 on the marginalportions thereof to form a stacked assembly with the plurality ofspacers slightly separated from and surrounding the sheets 1, 2 and 3.The stacked assembly is made into a unitary structure by having a weld 7formed along each edge side thereof after a pipe 7 has been suitablydisposed between the cover plate 4 and the metal base plate 3 on each ofthe longitudinal marginal portions as shown in FIG. 1. The pipes 7 serveto evacuate the space between the metal base plate 3, the cover plate 4and the spacers 6 and also to circulate a flow of inert gas through thespace. After the space has been cleaned with the inert gas, the pipesare hermetically cut and a suitable length of each pipe is sealed to thestacked assembly.

The assembly thus formed is then placed into a heating fumnace (notshown) at a temperature of from 800 to 1000 C. for a suitable period oftime, for example, a period of time of from 30 to 60 minutes for eachinch of the thickness of the assembly. After the lapse of the heatingtime just described, the heated assembly is removed from the furnace andimmediately hot rolled to reduce it from 50 to The temperature of theassembly at the completion of he rolling operation is preferably equalto or higher than 700 C. Then the hot rolled assembly is allowed to coolto room temperature and the cooled assembly is trimmed along its edgesand the cover plate is removed from the finished composite plate.

An assembly thus produced was tested and exhibited a shearing strengthon the order of from 10 to 30 kgs./ mm. and a workability suitable forvarious working operations.

In FIG. 2 wherein like reference numerals have been employed to identifythe components corresponding to those shown in FIG. 1, there isillustrated a stacked assembly similar to that shown in FIG. 1 exceptingthat the cover plate 4 is replaced by another stacked assembly portion.Titanium veneers ll, 1' and mother plates 2, 2 and base plates 3, 3'have been preliminarily treated in the same manner as above described inconjuncti n with FIG. 1 and then a stacked assembly portion 1, 2, 3 isput in mirror-image relationship upon another stacked assembly portion1, 2, 3 with a parting sheet 5 and a plurality of spacers 6 interposedthere/between. Then 6 assembly is trimmed along its edges and the coverplate is removed from the finished composite plate.

The composite metallic plates thus produced were tested and exhibited ashearing strength on the order of from 10 the entire assembly can beheated and rolled in the same 5 to 30 kgs./mm and a workability suitablefor various manner as above described in conjunction with FIG. 1.working operations. In this case, a pair of the finished compositemetallic In FIG. 4, wherein the like reference numerals have plates areproduced from each assembly such as shown in been employed to identifythe components corresponding FIG. 2. to those shown in FIG. 3 there isillustrated a stacked Referring now to FIG. 3 of the drawings, there is10 assembly similar to that shown in FIG. 3 excepting that illustratedan assembly of a titanium sheet superposed the cover plate 13 isreplace-d by another stacked asupon a mother metal plate composed of aniron alloy sembly portion. Titanium sheets 11, 11' and mother accordingto the invention without the mother metal metal plates 12, 12' of theinvention have been preliminplate being bonded to a base plate. Atitanium sheet, arily treated in the same manner as above described insuch a mother metal plate and a cover plate of any suitconjunction withFIG. 3 and then a stacked assembly porable material are machined to thedesired dimensions tion 11, 12 is put in mirror-image relationship uponanrespectively. Then one face of the titanium sheet and other stackedassembly portion 11, 12 with a parting one face of the mother plate tobe bonded to each other sheet 14 and a plurality of spacers 15interposed thereare mechanically polished and chemically cleaned.between. Then the entire assembly can be heated and As shown in FIG. 3,the titanium sheet 11 thus treated rolled in the ame manner as abovedescribed in conjuncis put upon the mother plate 12 also preliminarilytreated tion with FIG. 3. In this case a pair of the finished comwiththe treated faces of both members contacting each posite metallic platesare produced from each assembly other and being in register. Then thecover plate 13 is such as shown in FIG. 4. superposed on the exposedface of the titanium sheet 11 To illustrate the results of the inventionthe shearing with a parting sheet of any suitable material 14sandstrength and bending properties of various composite wichedthere-between and with a plurality of spacers of metallic plates havinga bonding layer and produced in any suitable material 15 interposedbetween the cover accordance with the invention are listed in Table Itoplate and the mother plate on the marginal portions theregether withthe chemical compositions of the metallic of to form a stacked assemblywith the plurality of bonding materials used. The titanium used was acomspacers slightly separated from and surrounding the mercially puregrade and had acomposition including by titanium and parting sheets. Thestacked assembly is Weight, 99.5% (min) Ti, 02-08% C, .02-.15% Fe, .02-made into a unitary structure by having a weld 16 formed .10% Si,.0l-.10% 0 100 ppm. (max) H and .001- along each edge side thereof aftera pipe 17 has been .10% N while the base plate metal used was ASTM typesuitably disposed between the cover plate 13 and the AZOIGB steelincluding, by weight, .24 (max) C, .15 metal mother plate 12 on each ofthe longitudinal margi- 30% Si, 80% (.max.) Mn, 035% (max-.) P, 04% nalportions as shown in FIG. 3. The pipes 17 serve (max) S for a-thicknessof at most 1 in.

TABLE I Composition of mother metal in percent Thickness of ShearingBending Specime Base metal plate in mms. Strength, Nu (Titanium kgslmmflC Si Mn P S Mo V Nb Zr W Mother metal) Inwardly outwardly ASIMA201GB .00.10 .50 .009 2+12 24.3 Good Good. ASTMA20lGB .04 .22 .43 .010 2+8 20.4-do Do. ASTMA20lGB .05 .24 .66 .011 2+8 18.1 do Do. ASIM-AZOIGB-.. .08.18 .51 .011 2+8 17.6 do Do. E ASTM-AZOIGB... .06 .26 .44 .013 2+8 17.1do Do.

to evacuate the space between the metal mother plate 12, the cover plate13 and the spacers 15 and also to circulate a flow of inert gas throughthe space. After the space has been cleaned with the inert gas, thepipes are hermetically cut and a suitable length of each pipe is sealedto the stacked assembly.

The assembly thu formed is then placed into a heating furnace (notshown) at a temperature of from 800 to 1000 C. for a suitable period oftime, for example, a period of time of from 30 to 60 minutes for eachinch of the thickness of the assembly. After the lapse of the TABLE IIComposition of mother metal in percent Thickness of Shearing BendingSpecimen plate in mms. Strength, N0. (Titanium-lkgs/rnmfi C Si Mn P S MoV Nb Zr W Mother metal) Inwardly Outwardly A l0 21 41 018 2+8 B .08 .18.40 .011 3+13 C 12 20 50 010 2+8 D 10 23 54 011 2+10 E .11 25 .43 .0102+ heating time just described the heated assembly is removed from thefurnace and immediately hot rolled to reduced it firom 50 to 80%. Thetemperature of the assembly at the completion of the rolling operationis preferably equal to or higher than 700 C. Then the hot rolledassembly From the foregoing, it will be appreciated that the object ofthe invention has been accomplished by the provision of special ironalloys used as bonding metals and mother plate metals in which thealloying metal is taken from the group consisting of molybdenum, vanaisallowed to cool to room temperature and the cooled dium, niobium,zirconium and tungsten.

While the invention has been described in the terms of a compositemetallic plate including .a titanium lamination bonded to one face of amother metal plate or through said mother metal plate to a metal baseplate, it is to be understood that a pair of titanium sheets can in thesame manner be bonded to both faces of the mother metal plate or throughrespective intermediate mother metal plates to both sides of a baseplate.

What is claimed is:

1. A composite metal plate comprising an iron alloy sheet and a veneerof titanium bonded to at least one face of said iron alloy sheet, saidiron alloy sheet consisting essentially of iron and an alloying elementtaken from the group consisting of molybdenum, vanadium, niobium,zirconium, and tungsten, said element being present in an amount of atleast equal to 0.3% by weight of the alloy.

2. A composite metal plate comprising an iron alloy mother plate and aveneer of titanium bonded to at least one face of said mother plate,said iron alloy mother plate consisting essentially of iron and analloying metal taken from the group consisting of 0.3 to 10.0% by weightof molybdenum, 0.3 to 10.0% by weight of vanadium, 0.3 to 10.0% byweight of niobium, from 0.3 to 6.0% :by weight of zirconium, and from0.3 to 10.0% by Weight of tungsten.

3. A composite metal plate comprising an iron alloy mother plate and aveneer of titanium bonded to at least one face of said mother plate,said iron alloy mother plate consisting essentially of iron and analloying metal taken from the group consisting of 1.0 to 4.0% by Weightof molybdenum, 1.0 to 3.0% by weight of vanadium,

0.5 to 1.5% by weight of niobium, 0.5 to 1.0% by weight of zirconium,and 1.0 to 1.5% by weight of tungsten.

4. A composite metal plate comprising a base plate comprising a metaltaken from the group consisting of iron and steel, a veneer of titaniumadjacent at least one face of said base plate, and a bonding materialbonded between said titanium veener and said base plate, said bondingmaterial consisting essentially of iron and an alloying metal taken fromthe group consisting of 0.3 to 19. 0% by weight molybdenum, 0.3 to 20.0%by Weight vanadium, 0.3 to 15.0% by weight niobium, 0.3 to 8.0% byweight zirconium, and 0.3 to 18.0% by weight tungsten.

5. A composite metal plate comprising a base plate comprising a metaltaken from the group consisting of iron and steel, a veneer of titaniumadjacent at least one face of said base plate, and a bonding materialbonded between said titanium veneer and said base plate, said bondingmaterial consisting essentially of iron and an alloying metal taken fromthe group consisting of 1.0 to 5.0% by Weight of molybdenum, 1.0 to 5.0%by Weight of vanadium, 0.5 to 2.0% by Weight of niobium, 0.5 to 2.5% byweight of zirconium, and 1.0 to 2.0% by weight of tungsten.

References Cited by the Examiner UNITED STATES PATENTS 2,813,332 11/1957Keay 29-194 X 2,908,969 10/1959' Wagner 29198 X 2,993,269 7/1961 Kelley29-498 X HYLAND BIZOT, Primary Examiner.

0.3 TO 10.0% BY WEIGHT OF NIOBIUM, FROM 0.3 TO 6.0% BY WEIGHT OFZIRCONIUM, AND FROM 0.3 TO 10.0% BY WEIGHT OF TUNGSTEN.
 2. A COMPOSITEMETAL PLATE COMPISING AN IRON ALLOY MOTHER PLATE AND A VENEER OFTITANIUM BONDED TO AT LEAST ONE FACE OF SAID MOTHER PLATE, SAID IRONALLOY MOTHER PLATE CONSISTING ESSENTIALLY OF IRON AND AN ALLOYING METALTAKEN FROM THE GROUP CONSISTING OF 0.3 TO 10.0% BY WEIGHT OF MOLYBDENUM,0.3 TO 10.0% BY WEIGHT OF VANADIUM,